
package io.renren.utils.util.message;


import java.io.Serializable;
import java.text.MessageFormat;
import java.util.HashMap;
import java.util.Locale;

import org.apache.log4j.Logger;


/**
 * General purpose abstract class that describes an API for retrieving
 * Locale-sensitive messages from underlying resource locations of an
 * unspecified design, and optionally utilizing the <code>MessageFormat</code>
 * class to produce internationalized messages with parametric replacement.
 * <p>
 * Calls to <code>getMessage()</code> variants without a <code>Locale</code>
 * argument are presumed to be requesting a message string in the default
 * <code>Locale</code> for this JVM.
 * <p>
 * Calls to <code>getMessage()</code> with an unknown key, or an unknown
 * <code>Locale</code> will return <code>null</code> if the
 * <code>returnNull</code> property is set to <code>true</code>.  Otherwise,
 * a suitable error message will be returned instead.
 * <p>
 * <strong>IMPLEMENTATION NOTE</strong> - Classes that extend this class
 * must be Serializable so that instances may be used in distributable
 * application server environments.
 *
 * @author Clark Liu
 */

public abstract class MessageResources implements Serializable {

	static Logger logger = Logger.getLogger(MessageResources.class.getName());
	
    // ------------------------------------------------------------- Properties


    /**
     * The configuration parameter used to initialize this MessageResources.
     */
    protected String config = null;

    public String getConfig() {
        return (this.config);
    }


    /**
     * The default Locale for our environment.
     */
    public static Locale defaultLocale = Locale.getDefault();


    /**
     * The <code>MessageResourcesFactory</code> that created this instance.
     */
    protected MessageResourcesFactory factory = null;

    public MessageResourcesFactory getFactory() {
        return (this.factory);
    }


    /**
     * The set of previously created MessageFormat objects, keyed by the
     * key computed in <code>messageKey()</code>.
     */
    protected HashMap formats = new HashMap();


    /**
     * Should we return <code>null</code> instead of an error message string
     * if an unknown Locale or key is requested?
     */
    protected boolean returnNull = false;

    public boolean getReturnNull() {
        return (this.returnNull);
    }

    public void setReturnNull(boolean returnNull) {
        this.returnNull = returnNull;
    }


    // ----------------------------------------------------------- Constructors


    /**
     * Construct a new MessageResources according to the specified parameters.
     *
     * @param factory The MessageResourcesFactory that created us
     * @param config The configuration parameter for this MessageResources
     */
    public MessageResources(MessageResourcesFactory factory, String config) {

        this(factory, config, false);

    }


    /**
     * Construct a new MessageResources according to the specified parameters.
     *
     * @param factory The MessageResourcesFactory that created us
     * @param config The configuration parameter for this MessageResources
     * @param returnNull The returnNull property we should initialize with
     */
    public MessageResources(MessageResourcesFactory factory, String config,
                         boolean returnNull) {

        super();
        this.factory = factory;
        this.config = config;
        this.returnNull = returnNull;

    }


    // --------------------------------------------------------- Public Methods



    /**
     * Returns a text message for the specified key, for the default Locale.
     *
     * @param key The message key to look up
     */
    public String getMessage(String key) {

    	return (getMessage((Locale) null, key));

    }


    /**
     * Returns a text message after parametric replacement of the specified
     * parameter placeholders.
     *
     * @param key The message key to look up
     * @param args An array of replacement parameters for placeholders
     */
    public String getMessage(String key, Object args[]) {

    	return (getMessage((Locale) null, key, args));

    }


    /**
     * Returns a text message after parametric replacement of the specified
     * parameter placeholders.
     *
     * @param key The message key to look up
     * @param arg0 The replacement for placeholder {0} in the message
     */
    public String getMessage(String key, Object arg0) {

    	return (getMessage((Locale) null, key, arg0));

    }


    /**
     * Returns a text message for the specified key, for the default Locale.
     * A null string result will be returned by this method if no relevant
     * message resource is found for this key or Locale, if the
     * <code>returnNull</code> property is set.  Otherwise, an appropriate
     * error message will be returned.
     * <p>
     * This method must be implemented by a concrete subclass.
     *
     * @param locale The requested message Locale, or <code>null</code>
     *  for the system default Locale
     * @param key The message key to look up
     */
    public abstract String getMessage(Locale locale, String key);


    /**
     * Returns a text message after parametric replacement of the specified
     * parameter placeholders.  A null string result will be returned by
     * this method if no resource bundle has been configured.
     *
     * @param locale The requested message Locale, or <code>null</code>
     *  for the system default Locale
     * @param key The message key to look up
     * @param args An array of replacement parameters for placeholders
     */
    public String getMessage(Locale locale, String key, Object args[]) {
    	
	    if (key == null) {
	    	return null;
	    }
	
		// Cache MessageFormat instances as they are accessed
	        if (locale == null)
	            locale = defaultLocale;
		MessageFormat format = null;
		String formatKey = messageKey(locale, key);
		synchronized (formats) {
		    format = (MessageFormat) formats.get(formatKey);
		    if (format == null) {
			String formatString = getMessage(locale, key);
			if (formatString == null) {
			    if (returnNull)
				return (null);
			    else
				return ("???" + formatKey + "???");
			}
			format = new MessageFormat(formatString);
			formats.put(formatKey, format);
		    }
	
		}
		return (format.format(args));

    }


    /**
     * Returns a text message after parametric replacement of the specified
     * parameter placeholders.  A null string result will never be returned
     * by this method.
     *
     * @param locale The requested message Locale, or <code>null</code>
     *  for the system default Locale
     * @param key The message key to look up
     * @param arg0 The replacement for placeholder {0} in the message
     */
    public String getMessage(Locale locale, String key, Object arg0) {

		Object args[] = new Object[1];
		args[0] = arg0;
		return (getMessage(locale, key, args));

    }



    /**
     * Return <code>true</code> if there is a defined message for the specified
     * key in the system default locale.
     *
     * @param key The message key to look up
     */
    public boolean isPresent(String key) {

        return (isPresent(null, key));

    }


    /**
     * Return <code>true</code> if there is a defined message for the specified
     * key in the specified Locale.
     *
     * @param locale The requested message Locale, or <code>null</code>
     *  for the system default Locale
     * @param key The message key to look up
     */
    public boolean isPresent(Locale locale, String key) {

        String message = getMessage(locale, key);
        if (message == null)
            return (false);
        else if (message.startsWith("???") && message.endsWith("???"))
            return (false); // FIXME - Only valid for default implementation
        else
            return (true);

    }


    // ------------------------------------------------------ Protected Methods


    /**
     * Compute and return a key to be used in caching information by a Locale.
     * <strong>NOTE</strong> - The locale key for the default Locale in our
     * environment is a zero length String.
     *
     * @param locale The locale for which a key is desired
     */
    protected String localeKey(Locale locale) {

        if (locale == null)
            return ("");
        //        else if (locale.equals(defaultLocale))
        //            return ("");
        else
            return (locale.toString());

    }


    /**
     * Compute and return a key to be used in caching information
     * by Locale and message key.
     *
     * @param locale The Locale for which this format key is calculated
     * @param key The message key for which this format key is calculated
     */
    protected String messageKey(Locale locale, String key) {

        return (localeKey(locale) + "." + key);

    }


    /**
     * Compute and return a key to be used in caching information
     * by locale key and message key.
     *
     * @param localeKey The locale key for which this cache key is calculated
     * @param key The message key for which this cache key is calculated
     */
    protected String messageKey(String localeKey, String key) {

        return (localeKey + "." + key);

    }


    // --------------------------------------------------------- Static Methods


    /**
     * The default MessageResourcesFactory used to create MessageResources
     * instances.
     */
    protected static MessageResourcesFactory defaultFactory = null;


    /**
     * Create and return an instance of <code>MessageResources</code> for the
     * created by the default <code>MessageResourcesFactory</code>.
     *
     * @param config Configuration parameter for this message bundle.
     */
    public static MessageResources  getMessageResources(String config) {

        if (defaultFactory == null)
            defaultFactory = MessageResourcesFactory.createFactory();
        return defaultFactory.createResources(config);

    }

    
//
//    /**
//     * Log a message to the Writer that has been configured for our use.
//     *
//     * @param message The message to be logged
//     */
//    public void log(String message) {
//
//        System.out.print("MessageResources: ");
//        System.out.println(message);
//        System.out.flush();
//
//    }
//
//
//    /**
//     * Log a message and exception to the Writer that has been configured
//     * for our use.
//     *
//     * @param message The message to be logged
//     * @param throwable The exception to be logged
//     */
//    public void log(String message, Throwable throwable) {
//
//        System.out.print("MessageResources: ");
//        System.out.println(message);
//        throwable.printStackTrace(System.out);
//
//    }


}
